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Transient Synovitis Of Hip

Transient Synovitis is the most common cause of hip pain and of limp in preschool and early grade school-age children.

Transient synovitis is also known as toxic synovitis, irritable hip, and observation hip.

The condition is seen most often in children between 3 and 8 years of age and manifests with the rapid onset of hip pain, limited joint range of motion, and limping (or an inability to walk, if the condition is severe). Often, the child has a history of an antecedent viral illness.

Synovitis of the hip may also be the first symptom of Legg-Calvé-Perthes disease, early juvenile arthritis, or ankylosing spondylitis. Hip irritability also may accompany osteomyelitis in the femur or pelvis or another bony lesion.

See Also: Hip Joint Anatomy
toxic synovitis

Transient Synovitis Causes

The Cause of transient synovitis is unknown, it can be related to viral infection, allergic reaction, or trauma

The disorder occasionally follows an upper respiratory tract infection, but the nature of this relationship is unknown. Some studies sought evidence of a bacterial or viral etiology, without success.

In one study, technetium bone scans showed a decrease in isotope uptake in the proximal femoral epiphysis in one fourth of the hips with synovitis. In these hips, rebound hyperemia was noted on follow-up scan 1 month later. Only one such patient later developed Legg-Calvé- Perthes disease. The significance of this finding is uncertain.

Another study found increased levels of proteoglycan antigen in children with both septic arthritis and transient synovitis.

See Also: Legg-Calvé-Perthes disease
Legg-Calvé-Perthes disease

Clinical Features

The usual presentation is a child with the fairly rapid onset of limping and subsequent refusal to walk or bear weight. This sometimes follows a recent upper respiratory tract illness, and parents may report a low-grade fever.

Boys are affected two to three times as frequently as girls. The onset peaks between 4 and 10 years, with a mean age at onset of approximately 6 years.

The examiner finds a child in mild distress who will not bear weight or walk or who does so reluctantly and with an antalgic limp.

The range of motion of the affected hip is moderately limited by pain and spasm, and the hip is held in flexion. Gentle short-arc motion may be tolerated, but an attempt to extend fully or internally rotate the hip is resisted.

The irritability of the hip is usually several grades less severe than in a child with septic arthritis. Low-grade fever may be present.

Transient synovitis resolves spontaneously:

  • Usually the child presents when unwilling to walk or when limping severely. The period of non-walking generally lasts 1 or 2 days.
  • The child then walks with a limp and has reduced range of motion of the hip for another few days to usually not more than 2 weeks before returning to normal.
  • An ultrasonographic study demonstrated that the effusion persisted longer than 1 week in 58% of patients.

Diagnostic Studies

The laboratory evaluation may show mild elevations in the WBC count, ESR, and CRP level.

Plain radiographs of the pelvis are usually normal or may show slight joint space widening. When joint space widening and a smaller femoral ossific nucleus on the involved side are evident, one can make a presumptive diagnosis of early Legg-Calvé-Perthes disease.

Ultrasonography of the hip is useful in documenting the presence of an effusion in the hip joint. Ultrasonography is often performed before hip aspiration to be certain that the clinical findings are accompanied by an effusion.

Transient Synovitis Ultrasonography

Kocher criteria that suggest an infectious etiology:

Distinguishing septic arthritis of the hip from transient synovitis is a common problem; when three of four of the following Kocher criteria are present, the diagnosis of septic arthritis is made in more than 90% of cases:

  1. WBC count higher than 12,000 cells/mL,
  2. ESR higher than 40,
  3. inability to bear weight,
  4. temperature higher than 38.6°.

Differential Diagnosis

The Differential Diagnosis of Transient Synovitis Of Hip include:

  1. septic arthritis: it’s the most important diagnosis to exclude.
  2. Legg-Calvé-Perthes disease.
  3. early juvenile arthritis.
  4. ankylosing spondylitis.
  5. osteomyelitis in the femur or pelvis.

Transient Synovitis Treatment

Treatment begins almost spontaneously because the child refuses to walk or be moved and thereby rests the hip.

  1. Hip joint aspiration is commonly necessary to rule out septic arthritis and may be beneficial. The real purpose of aspiration is diagnostic, and the surgeon should have a low threshold for tapping the
  2. The child is placed on bed rest until the symptoms and signs are improving.
  3. NSAIDs may be used and often result in rapid improvement.
  4. In more severe cases, traction can be helpful for a few days.
  5. Hospital admission is appropriate when septic arthritis remains a possibility or when other diagnoses have not been eliminated.
See Also: Skeletal Traction

Close observation is essential and patients may require hospital admission, especially when the parents are not reliable.

Antibiotics should not be used because the process is not infectious, and antibiotic therapy confuses the

Rapid resolution of symptoms and return of range of motion are characteristic of transient synovitis.

Worsening symptoms suggest sepsis, and a prolonged course suggests chronic inflammatory conditions such as rheumatoid arthritis and seronegative spondyloarthropathies.


  1. Landin LA, Danielsson LG, Wattsgård C. Transient synovitis of the hip. Its incidence, epidemiology and relation to Perthes’ disease. J Bone Joint Surg Br. 1987 Mar;69(2):238-42. doi: 10.1302/0301-620X.69B2.3818754. PMID: 3818754.
  2. Vijlbrief AS, Bruijnzeels MA, van der Wouden JC, et al: Incidence and management of transient synovitis of the hip: a study in Dutch general practice, Br J Gen Pract 42:426, 1992.
  3. Swann M, Ansell BM: Soft-tissue release of the hips in children with juvenile chronic arthritis, J Bone Joint Surg Br 68:404, 1986.
  4. Kesteris U, Wingstrand H, Forsberg L, et al: The effect of arthrocentesis in transient synovitis of the hip in the child: a longitudinal sonographic study, J Pediatr Orthop 16:24, 1996.
  5. Hill SA, MacLarnon JC, Nag D: Ultrasound-guided aspiration for transient synovitis of the hip, J Bone Joint Surg Br 72:852, 1990.
  6. Hardinge K: The etiology of transient synovitis of the hip in childhood, J Bone Joint Surg Br 52:100, 1970.
  7. Del Beccaro MA, Champoux AN, Bockers T, et al: Septic arthritis versus transient synovitis of the hip: the value of screening laboratory tests, Ann Emerg Med 21:1418, 1992.
  8. Millers Review of Orthopaedics -7th Edition Book.
  9. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
  10. John A. Herring. Tachdjian’s Pediatric Orthopaedics, 5th Edition.
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